I think comedians swing left or really libertarian most of the time (at least the decent ones). Comedians whose work is really timeless or based on social commentary seem to have to be far-removed enough from the mainstream, or the system, or whatever, so that they can mock it.

I'm sure there are plenty of comedians who could be considered "right-leaning", who work clean, and make audiences of 30-75 year old white folks chuckle at casino ballrooms.